The present invention relates to tubular tires for cycles and more particularly to those tires wherein the tire body is wholly and irremovably enclosed to form a toroidal ring and lacking of beads. Such tires, that are commonly known as tubular tires, are mounted on special wheel rims, that is without the flanges provided on the conventional wheel rims to engage the beads of a normal tire having an inflatable inner tube that is separable from the tire body upon dismounting the tire from the rim. The invention relates to improved tires of the above mentioned type as well as, in a particular embodiment, to an enclosed tubular tire without an independent air tube that is anyhow provided with a sort of "beads" that make possible the mounting onto a conventional wheel rim. Finally the invention relates to a method for manufacturing such tires.
Tubular tires are mainly intended for the agonistic use thanks to their lightweight, minimum power absorption due to hysteresis, flexibility and high speed of elastic response. As a drawback these tires have some negative features since they are more expensive, laborious to be employed and difficult to be repaired when punctured. Namely the tires are built from a tire body or carcass formed by one or more bands of rubberized fabric having the hems joined together to form a closed toroidal structure. An inner or air tube is placed within the carcass and a rubber tread band is applied onto the radially outer surface. Upon vulcanizing the rubber band forms the outer tread whereas the inner tube is intimately bound to the body. According to the prior art that provides both for a sewing and for an overlapping junction of the edges (by glueing and/or vulcanizing) the junction area is placed on the inner circumference of the tire, i.e. the part that is to contact the wheel rim and is possibly protected by a reinforcement strip running along the full inner circumference of the tubular tire, see for example French Pat. No. 2,347,216. The junction is always located in correspondence of the minimum diameter of the toroidal ring so that, for example, this latter can be unsewn to expose the inner tube when a repair is needed.
Beyond the repair, also the installation of the tire is rather laborious since the assembly wheel rim-tubular tire requires a glueing of the members by means of a special putty to avoid that the tire and the rim get detached when in use. The presence of putty is a further obstacle when dismounting the tire for repair, and under particular stresses the putty does not ensure that the tire cannot move with respect to the rim, both longitudinally and transversely and detach from this latter with consequences that are easy to realize.